Answers to Questions Asked During the Webinar
Question: What are the intersection types that Vistro analyzes?
Answer: Vistro analyzes Signals, Two-way Stops, All-way Stops and Roundabouts.
Question: What analysis methodologies does Vistro calculate?
Answer: Vistro calculates the following methodologies: Highway Capacity Manual (HCM) 6th Edition, HCM 2010 and HCM 2000, the Canadian Capacity Guide (CCG) 3rd Edition, Intersection Capacity Utilization (ICU), Circular 212 Planning method, and the Kimber method.
Question: Can Vistro be adapted for local conditions?
Answer: Yes, there are many parameters that are editable to allow users to replicate local conditions, such as adjustments to driver behavior for gap acceptance and saturation flow. Additionally, Vistro can analyze either right-hand drive or left-hand drive conditions.
Question: How many legs can be modeled at an intersection in Vistro?
Answer: Vistro can model up to 8 legs at any intersection.
Question: For signal timing, how many Rings and Barriers can be modeled?
Answer: Vistro can model up to 4 Rings and 8 Barriers in its signal controller.
Question: Can Vistro analyze an all-pedestrian phase (ped scramble)?
Answer: Yes, a pedestrian signal group (phase) can be defined and put into sequence in its own barrier.
Question: Is there a graphical view of the signal timing? Is it interactive?
Answer: Yes, once the signal phasing and timing have been defined and put into sequence in the Traffic Control workflow table, a graphical timing diagram is shown at the bottom, which can be edited by sliding the timings for any of the signal groups (phases).
Question: Can Vistro model two intersections running-off of the same signal controller? For instance, at diamond interchanges or at closely spaced physically off-set intersections?
Answer: Yes, this is accomplished by selecting the same Controller ID for both intersections, and adjusting movement control types to include overlaps where needed. We include an example file with the installation with this coding for a tightly spaced diamond interchange (see the Signal Controllers folder in the Examples directory).
Question: Can Vistro analyze other types of interchanges such as SPUI or DDI or maybe a CFI?
Answer: Yes, Vistro can model these alternative intersection types. We will show how to do this in a later PTV Talks session.
Question: Does Vistro have a time-space diagram? Is it easy to edit? How is it created?
Answer: Yes, this will be covered in detail in a future PTV Talks session. Vistro provides a time-space diagram and users can slide offset values to adjust green bands interactively. The time-space diagrams are created once Routes are defined along a series of intersections. Routes can be along straight corridors, or include a series of turns along multiple roadways.
Question: Can you set a master controller/intersection in Vistro?
Answer: Yes, a Signal Coordination Group in Vistro (more to come on that topic in our next Vistro webinar on traffic signal optimization) can have one signalized controller selected as the Master Controller, which locks the offset at this controller to a zero offset. When the Master Controller is set in the Coordination Group Menu, the offset value at this intersection is set to zero, and all other signal controllers in the coordination group are automatically calculated relative to the Master Controller (if previously set).
Question: Does Vistro perform signal timing optimization?
Answer: Yes, this will be covered in detail in a future PTV Talks session. Vistro performs local or network-wide signal optimization. The network optimization includes route-based optimizations and user-defined weighting of both performance criteria components and route prioritization.
Question: Does Vistro allow for importing/exporting? What are the types of data that can be imported or exported?
Answer: Yes, Vistro allows for many imports/exports.
Imports include: Volume data (CSV), Open Street Map (OSM) data, Synchro data, and Visum data.
Exports include: Volume data (CSV), ANM and RBC files to Vissim, SVG and HTML files.
Question: Does Vistro show animation (moving vehicles)?
Answer: Yes, Vistro has a “Preview in Vissim” option that can be called directly from Vistro, which will bring-up a new window with a visualization of the simulation in the Vissim previewer interface with just one-click. This functionality does not require a Vissim license. In the previewer, you can pan, zoom and switch between 2D and 3D views. If moving to a full microsimulation is desired for further analysis, then the Vistro network can be exported to Vissim fully (which does require a Vissim license to import).
Question: Can additional volumes be assigned to the Vistro network?
Answer: Yes, this will be covered in detail in a future PTV Talks session. Vistro performs trip generation, distribution and assignment to allow analysis of trips added from one or many site locations for multiple scenarios.
Question: Can Vistro analyze preemption or transit signal priority (TSP)?
Answer: TSP simulation is beyond the scope of a deterministic tool like Vistro, and should be done in Vissim. There are certain estimations that could be coded into Vistro for planning purposes.
Question: Can adaptive traffic signal timing be analyzed in Vistro?
Answer: Adaptive signal control is beyond the scope of a deterministic tool like Vistro, and should be done in Vissim.
Question: What output reports does Vistro provide?
Answer: Vistro creates detailed reports, including report-ready tables and graphical figures.
Tabular reports include: Intersection Analysis Details and Summary, Turning Movement Volumes, Fair-Share Volumes and Percentages, Signal Warrants, Trip Generation, Trip Distribution, Trip Assignments.
Graphical reports include: Study Intersections, Lane Configurations, Traffic Volumes (Base, In-process, Future Background, Net-New Site, Other, Future Total), Traffic Conditions, Time-Space Diagrams (Flowing Off, Arterial Bands – both one-way and two-way), Fair-share Volumes, Fair-share Percentages).
Additionally, there are many on-network graphics that can be shown in Vistro, which can also be reported either through export (to SVG, HTML) or via screen capture.